Getting all Page Restrictions for a group

From what I have seen, the closest way through the Confluence API is to get the pages for a space:

PageManager#getPagesWithPermissions(Space space)

and then scour the returned pages for restrictions linked to the group. Is there another more efficient way of getting the page permissions for a group?

I can see ContentPermissionDao looks like the required entry point but it does not appear to be accessible via a component…